PILOT PRODUCTION, FABRICATION AND EVALUATION OF PROMISING TITANIUM ALLOYS. Period Covered: April 1, 1955 to August 31, 1957
Approximately 300 pounds of Ti--7Al--3Mo alloy were fabricated to bar stock and distributed to various jet engine manufacturers. About 70 pounds of hot-rolled centerless-ground bar was sent to Thompson Products, Inc. They were highly successful in manufacturing 140 J-57 7th stage compressor blades from this material. The endurance limit for blades bench-tested at room temperature under completely reversed stress was 75 000 psi, 5000 psi higher than Ti--6A1--4V alloy blades of the same configuration. Tensile properties for specimens cut from blades and heat treated- 1560 deg F-1/2 hour-air cooled, 1020 deg F-24 hours were as follows: 170,000 psi ultimate tensile strength, 167,000 psi 0 2% offset yield strength, 49% reduction in area, and 16% elongation. As a result of the promising preliminary evaluations, Pratt and Whitney Aircraft, Division of United Aircraft is preparing to engine test these blades. Johnston and Funk Titanium Corporation was successful in producing, on an experimental basis, wire in sizes down to 0.020 in. diameter from Ti--7Al--3Mo 9/32 in. diameter rod. No difficulty in supplying production quantities is anticipated. The highstrength condition produced by applying the heat treatment: 1800 deg F-1 hour-water quench 1000 deg F-2 hours to equiaxed Ti--7A1--3Mo alloy material was found to be unstable to aging under stress at 800 deg F. Tests conducted by Eaton Manufacturing Company indicated that the alloy is stressrelieved by 2 hours at 1300 deg F. The Ti--7A1--3Mo alloy shows considerable promise. This is a fact implicit in the production by Cramet Inc., of 1500 to 2000 pounds of Ti--7A1--3Mo material for sale, and the announcement by Rem-Cru Titanium, Inc, of the availability of experimental quantities of their version of the alloy containing 6 1/2% aluminum and 3 3/4% molybdenum. (auth)
- Research Organization:
- Illinois Inst. of Tech., Chicago. Armour Research Foundation
- NSA Number:
- NSA-12-007845
- OSTI ID:
- 4352211
- Report Number(s):
- WADC-TR-54-54(Pt.II); AD-15101
- Country of Publication:
- United States
- Language:
- English
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